Purcells

Rising temperatures in the alpine may change the snowpack dramatically, especially on solar aspects. Forecasters are working with little information this early in the season. Share your observations through the Mountain Information Network. MIN

Fair - Due to the number and quality of field observations

An arctic high continues to dominate the weather pattern over western Canada and is not forecast to move out of the area until Tuesday or Wednesday next week. In the meantime, an above-freezing layer (AFL) of air will pass through the region between 1500 and 3000m bringing temperatures in that elevation band to as high as +5c., especially on solar aspects. Arctic air pooling in the valley bottoms will keep the temperatures well below freezing until the next storm system flushes out the cold air.

Reports of large avalanches triggered by explosives failing on facts at the base of the snowpack have been received from operators.  Surface sluffing of the recent snow in steep terrain has been mentioned as well as a few skier controlled, low density, size 1 avalanches.  The general feeling is that these low density size 1's were failing on the Sept. 23rd surface hoar.

The snowpack has been described by local observers as "extremely variable", with wind effect in all open alpine areas from the Northerly winds after the last storm. Surface hoar is widespread and observed to 4mm in sheltered locations, while windward slopes have been scoured down to bare rock in some locations. Cold arctic air and temps down to -20 in some areas have promoting surface facetting. The above-freezing-layer of warm air, now  moving through the region could dramatically alter the snowpack.  There may be a radical difference in the snowpack depending on the aspect :ie, north or south facing slopes.